Touchpads and graphic tablets are graphics input devices that cause data to be input to a computer display in response to stimulation of a position sensitive surface. Such stimulation can be tactilely generated, wherein a pressure sensitive surface is physically contacted by a user's finger or stylus. Or, the position sensitive surface might sense the presence of a stylus that is in close proximity to, but that does not physically touch, the surface. Accordingly, for purposes of the present invention "position sensitive surface" means both surfaces that are tactilely stimulated and surfaces that are stimulated by the close proximity of a contact object, such as a stylus.
In the case of touchpads, a user can control the positioning of a cursor on a display by pressing against the touchpad and moving the user's finger. Typically, the touchpad is part of the same physical assembly as is the display. When a user lifts the finger from the touchpad and then places it back down on the pad, the position of the cursor on the display is not relocated, but remains in its position on the display until the finger moves. In this sense, a touchpad can be thought of as a relative input device, much like a mouse. Indeed, touchpads are used to undertake the functions traditionally undertaken by mice.
On the other hand, graphic tablets are remote from their associated displays, and are absolute input devices, in that once an input stylus (used to exert pressure against or otherwise stimulate the tablet) is lifted from the tablet and then placed back down onto the tablet, the cursor is instantaneously relocated to a new position on the display. In effect, the input area defined by the tablet is mapped absolutely to the display. With this combination of structure, graphic tablets are rendered suitable for drawing objects on a display (and converting drawing strokes to electronic signals).
As recognized by the present invention, while each of touchpads and graphic tablets are effective for their intended purpose, combining the functions in a single device would be advantageous for several reasons. First, the versatility of such a device obviates the need for two separate devices. Also, the size of the graphics window can be established as appropriate for rapid cursor control or for high-resolution graphics input. Moreover, by switching between functions, the present invention recognizes that certain drawbacks inherent in graphic tablets can be overcome, such as unintended lines or contour discontinuities being input as a result of lifting and then once again pressing a stylus onto the input surface.
As still further recognized herein, however, such switching between relative (touchpad) input modes and absolute (graphic tablet) input modes should be easy, and should not distract the user's attention from the display. In other words, the present invention recognizes that it would be advantageous to provide visual feedback that is clearly representative of the invoked mode. Moreover, the present invention recognizes a need to easily convert existing touchpads and graphic tablets into dual-purpose input devices.
In addition to the above considerations, the present invention recognizes that a user of a pressure-sensitive graphic tablet might occasionally unintentionally input data via the tablet when the user's arm is rested on the tablet during data input with a stylus. Furthermore, the present invention recognizes a need to provide a simple, inexpensive device for converting a portion of a cursor control input device into a cursor control area having cursor control characteristics that are different from those of the remainder of the input device.
Accordingly, it is an object of the present invention to provide a system and method for establishing a graphics input device having both a relative input mode and an absolute input mode. Another object of the present invention is to provide a system and method for establishing a graphics input device having both a relative input mode and an absolute input mode, which provides visual feedback that represents the particular mode which is invoked. Still another object of the present invention is to provide a system and method for establishing a graphics input device having both a relative input mode and an absolute input mode that is easy to use and cost-effective. Another object of the present invention is to provide a device which permits a user of a graphic tablet to rest his or her arm without unintentionally inputting data. And, a further object herein is to provide a simple, one-piece stick-on device which cooperates with software for converting a portion of a position sensitive input device to a cursor control area having characteristics that are different from those of the remainder of the input device.